Heretofore separation of guayule bagasse from solvent solutions was generally done either by expression or filtration. Such methods required a solvent rinse to completely recover the miscella.
U.S. Pat. No. 2,390,860 relates to the purification of plant rubbers such as guayule by utilizing a solvent mixture always containing 50 percent or more of a resin solvent and 50 percent or less of a rubber solvent. Such a method generally forms a two-phase system and results in extraction of guayule resin.
U.S. Pat. No. 2,549,763 relates to the recovery of betaine from guayule plant extract by utilizing a polar solvent, obtaining a phase separation, and then adding a phosphate compound to the aqueous phase.
U.S. Pat. No. 2,618,670 relates to a process for deresinating rubber from plants by utilizing water-miscible resin solvents such as methyl ethyl ketone. Additionally, a methyl ethyl ketone-water azeotrope is utilized.
U.S. Pat. No. 2,572,046 relates to using a water miscible solvent to form a solution of the guayule utilizing the resin phase and adding a hydrocarbon such as pentane solvent thereto to form a two-phase system. The resin component is then extracted from the hydrocarbon phase. A small amount of hydrocarbon solvent is utilized to form the two-phase system.
U.S. Pat. No. 4,435,337 relates to a process for isolating rubber, resins, water-solubles and bagasse from comminuted guayule by drying the plant material until it contains a moisture content of from about 5 to about 25 percent by weight, deresinating the plant by utilizing an essentially anhydrous oxygenated organic solvent containing acetone and subsequently recovering rubber, water-solubles and by-products bagasse by water flotation.
The above patents are not pertinent in that they (1) do not utilize a resin-rubber solvent system, (2) do not use water to create a phase separation, (3) do not address the problem of the separation of bagasse solid particles from the resin-rubber miscella, and the like.